FIG. 1 shows a diagram known from the state of the art of a drive train of a motor vehicle with a drive unit 1 and an automatic transmission 2 switched between the drive unit 1 and an output 3, whereas the automatic transmission 2 is carried out as an automatic or automated manual transmission and comprises several shifting elements 4 formed as couplings and/or brakes. A start-up element formed as a converter 5 is positioned between the drive unit 1 and the automatic transmission 2, whereas one converter lock-up clutch 6 is allocated to the converter 5. Of the converter 5, FIG. 1 shows a turbine wheel 7 and a pump wheel 8. FIG. 1 also shows a transmission selector lever 9 and a transmission control device 10. The operation of the automatic transmission 2, including the converter 5 and the converter lock-up clutch 6, is controlled and/or governed with the assistance of the transmission control device 10. Through the transmission selector lever 9, a shift position for the automatic transmission 2, namely at least one of the shift positions N (neutral), P (park), D (drive-forward travel) and R (reverse travel), is selected.
In practice, it is already known from practice to monitor an automatic transmission for whether, if a shift position of the automatic transmission that is free of a frictional connection is selected through the transmission selector lever, an unwanted frictional connection has built up. However, it has so far not been possible to reliably perform this monitoring.